GHSA-6vfc-qv3f-vr6c is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in markdown-it. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-6vfc-qv3f-vr6c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Uncontrolled Resource Consumption in markdown-it
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
markdown-itnpmDescription
Impact
Special patterns with length > 50K chars can slow down parser significantly.
const md = require('markdown-it')();
md.render(`x ${' '.repeat(150000)} x \nx`);
Patches
Upgrade to v12.3.2+
Workarounds
No.
References
Fix + test sample: https://github.com/markdown-it/markdown-it/commit/ffc49ab46b5b751cd2be0aabb146f2ef84986101
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | markdown-it | all versions | 12.3.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for markdown-it. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update markdown-it to 12.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6vfc-qv3f-vr6c is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-6vfc-qv3f-vr6c is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-6vfc-qv3f-vr6c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-6vfc-qv3f-vr6c in your dependencies?
O3 detects GHSA-6vfc-qv3f-vr6c across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.